acute Inflammation

Question 1

What are the signs of acute inflammation

Answer 1

Heat
Redness
Swelling
Pain
Loss of function

Question 2

Define acute inflammation

Answer 2

Redundant, complex, adaptive & protective response of vessels, resident cells & leucocytes to noxious stimuli

Question 3

How does acute inflammation work?

Answer 3

Inflammation brings cells & molecules of host defence from circulation to sites where they are needed, in order to eliminate offending agents & repair tissues

Lasts hours to days

Question 4

Give examples of causes of acute inflammation

Answer 4

Infections (bacterial, fungal, viral, parasitic) & microbial toxins

Tissue necrosis, ischemia, trauma, physical & chemical injury, irradiation

Foreign bodies

Immune reactions

Question 5

What are the morphologic hallmarks of acute inflammation?

Answer 5

Dilation of blood vessels

Activation & recruitment of leucocytes

Active exudation of fluid in extravascular tissue

Question 6

What are the mediators in acute inflammation & where are they produced?

Answer 6

Vasoactive amines (histamine, serotonine)
- released/produced by mast cells, basophils, platelets

Inflammatory lipids (prostaglandins, leukotrienes)
- produced by mast cells, leukocytes

Complement (C5a, C3a)
- produced in liver

Cytokines (IL-1, TNF, IL-6)
- produced by macrophages, endothelial cells, mast cells

Question 7

Which inflammatory mediators cause vasodilation in acute inflammation?

Answer 7

Inflammatory lipids (prostaglandins, leukotrienes)

Question 8

Which inflammatory mediators cause increased vascular permeability in acute inflammation?

Answer 8

Vasoactive amines

Complement (C5a, C3a)

Inflammatory lipids

Cytokines (IL-1, TNF)

Question 9

Which inflammatory mediators cause leukocyte recruitment & activation in acute inflammation?

Answer 9

Inflammatory lipids

Complement

Cytokines

Question 10

Which inflammatory mediators cause pain in acute inflammation?

Answer 10

Inflammatory lipids

Question 11

Which inflammatory mediators cause tissue damage in acute inflammation?

Answer 11

Release of neutrophilic cytoplasmic granular content (enzymes)

Reactive oxygen species (produced by neutrophils & leukocytes)

Question 12

What are the possible consequences of acute inflammation

Answer 12

Complete resolution

Scarring or fibrosis

Progression to chronic inflammation

Question 13

describe complete resolution as an outcome of acute inflammation

Answer 13

Complete resolution happens when:
- injury is limited in extent
- There is minimal tissue destruction & damaged parenchymal cells can regenerate

This leads to clearance of offending agent & full tissue regeneration

Question 14

describe scarring/fibrosis as an outcome of acute inflammation

Answer 14

Scarring (fibrosis) occurs when:
- There is substantial tissue destruction
- inflammatory injury affects tissues incapable of regeneration
- Fibrin exudation in tissues or serous cavities (pleura, peritoneum) can’t be cleared

In these cases, connective tissue replaces damaged area, forming mass of fibrous tissue

Question 15

describe progression to chronic inflammation as an outcome of acute inflammation

Answer 15

Acute inflammation becomes chronic when:
- injurious agent persists
- There is interference in normal healing

Question 16

Describe acute phase response in acute inflammation

Answer 16

systemic reaction to acute inflammation, involving:
- Pyrexia (fever)
- Leukocytosis (increased WBC count)
- Metabolic changes
- Changes in plasma proteins (acute phase proteins, APPs)

Question 17

How is acute inflammation similar to a dripping tap?

Answer 17

Leakage of inflammatory cytokines acts both locally & systemically

This “dripping effect” triggers widespread systemic changes

Continuous release of inflammatory mediators leads to acute phase response

Question 18

What causes pyrexia?

Answer 18

Fever is caused by increase in hypothalamic set point, leading to elevated core body temp

Fever is triggered by exogenous or endogenous pyrogens, which activate host immune response

Question 19

Describe the pyrexia pathway

Answer 19

1. Exogenous pyrogens (e.g. bacteria) & endogenous triggers (e.g. phagocytosis, tissue damage, immune complexes) stimulate:
2. Neutrophils & Macrophages, which release:
3. Endogenous pyrogens (IL-1, TNF, IL-6), leading to:
4. Increased production of PGE₂ (Prostaglandin E₂), which acts on:
5. Hypothalamus, increasing body temp via vasoconstriction & shivering

Question 20

How can pyrexia be regulated?

Answer 20

NSAIDs act as antipyretics by inhibiting PGE₂ synthesis, reducing fever

Question 21

What is a biomarker?

Answer 21

biological molecule that is objectively measured & is indicator of normal or abnormal process, or of a condition or disease

Question 22

What are the positive APP biomarkers of inflammation?

Answer 22

Question 23

What are the negative APP biomarkers of inflammation?

Answer 23

Question 24

What are the types of exudate in acute inflammation?

Answer 24

Question 25

What is transudate in acute inflammation?

Answer 25

Extravascular filtrate of protein & cell poor fluid

Caused by increased hydrostatic pressure or due to decreased colloido-osmotic pressure (or combination)

It is accumulated in body cavities & extracellular compartments

Fluid appears grossly clear & watery